Guidewire and catheter with rotating and reciprocating symmetrical or asymmetrical distal tip

ABSTRACT

A guidewire or a catheter for crossing vascular occlusions comprises a shaft having a proximal end and a distal end, and a drive member having a proximal and a distal end, the drive member being rotatably disposed within and along a longitudinal axis of the guidewire shaft. An actuator is connected to the proximal end of the drive member, the actuator imparting a rotation to the drive member. An asymmetrical rotating tip is attached to the distal end of the drive member and driven in rotation about the longitudinal axis of the shaft by the drive member. The rotating tip may include a protruding portion that projects from a plane defined by an outer surface of the guidewire shaft to render the rotating tip asymmetrical with respect to the longitudinal axis of the shaft. The protruding portion creates a volume of revolution as the asymmetrical tip rotates, which facilitates crossing a vascular occlusion by displacing and exerting pressure on stenotic material causing the occlusion. Alternatively, the rotating tip may be symmetrical. A coupling member may be attached to the distal end of the shaft and may include a distal angled surface. When the tip includes a mating angled surface, rotation of the drive member causes the tip to undergo both a reciprocal and a rotational motion along and about the longitudinal axis of the shaft.

RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.08/969,814, now U.S. Pat. No. 6,183,432, entitled Guidewire and Catheterwith Rotating and Reciprocating Symmetrical or Asymmetrical Distal Tip,filed Nov. 13, 1997.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to guide wires and catheters for crossing, openingand/or widening a channel through a totally or partially occludedbiological vessel, such as a blood vessel.

2. Description of the Related Art

There are a number of disease conditions involving stenosis, which isthe narrowing or obstruction of the interior passage, or lumen, ofarteries. These obstructions, generally known as occlusions, are foundin patients suffering from atherosclerosis, a condition characterized byan accumulation of fibrous, fatty or calcified tissue in the arteries.As these occlusions can partially or totally block the arterial flow,they can be potentially life threatening. Occlusions may be partial ortotal, may be soft and pliable or hard and calcified, and may be foundat a great variety of sites in the arterial system, including the aorta,the coronary and carotid arteries, and peripheral arteries.

Although the majority of interventional procedures such as balloonangioplasty, atherectomy, and the like bring some degree of relief tothe patient and improvement in the blood flow, total or near totalocclusions are difficult to treat, as the interventional tool, such asthe angioplasty balloon or the atherectomy catheter, often cannot reachand cross the occlusion site to carry out their intended functions. Thisis generally referred to as an inability to cross, and is the majorcause of failure of such procedures.

A number of different instruments have been proposed to open or to crossa totally or partially blocked blood vessel. One such instrument isdisclosed in U.S. Pat. No. 5,116,350 to Stevens. Stevens describes acatheter whose distal blunt tip moves back and forth in a ramming motionor whose cutting/abrading distal tip moves back and forth about an axis.Osypka, in U.S. Pat. No. 5,234,451 discloses an apparatus foreliminating occlusions and stenoses in body cavities. The device ofOsypka includes a combination of anvil and reciprocating internal hammerto ram the device through occlusions. The hammer repeatedly strikes theanvil to drive the device further within the cavity. Uflacker et al., inU.S. Pat. No. 5,243,997 propose a device to vibrate a guidewire. Thevibration induced thereon is asserted to facilitate the pushing of theguidewire past the obstruction. Solar, in U.S. Pat. No. 5,549,119discloses a vibrating tip catheter, the vibration being asserted toenhance the catheter's ability to cross tight lesions and stenoses.

These devices, however, suffer from a number of disadvantages. It isbelieved that the sharp back and forth ramming motions of some of thesedevices may possibly damage the vessel lining and lead to unwanted scartissue. On the other hand, the vibrating guide wires and tips are notbelieved wholly effective in crossing total occlusions without damagingthe vessel walls. Moreover, it is not believed that these devicespossess the ability to sufficiently enlarge an existing channel to allowother, larger, or more aggressive interventional tools to follow and toposition themselves across the occlusion.

What is needed, therefore, are improved guide wires and catheters thatare able to successfully navigate tortuous regions of a patient'svasculature and to create or enlarge a channel past an occlusion toallow other interventional tools to successfully perform their intendedtherapeutic functions. What is also needed are such guide wires andcatheters that are effective in opening or enlarging channels past anocclusion, while not damaging the vessel walls.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide improvedguide wires and catheters that are able to successfully navigatetortuous regions of a patient's vasculature and to create or enlarge achannel to allow other interventional tools to successfully cross thelesion.

It is a further object of the present invention to provide such guidewires and catheters that are effective in opening or enlarging channelspast an occlusion, while not damaging the vessel walls.

In accordance with the above objects and those that will be mentionedand will become apparent below, the guidewire for crossing vascularocclusions according to an embodiment of the present inventioncomprises:

a guidewire shaft having a proximal end and a distal end;

a drive member having a proximal and a distal end, the drive memberbeing rotatably disposed within and along a longitudinal axis of theguidewire shaft;

an actuator connected to the proximal end of the drive member, theactuator imparting a rotation to the drive member;

an asymmetrical rotating tip attached to the distal end of the drivemember and driven in rotation about the longitudinal axis of theguidewire shaft by the drive member, the asymmetrical rotating tipincluding a protruding portion that projects from a plane defined by anouter surface of the guidewire shaft to render the rotating tipasymmetrical with respect to the longitudinal axis of the shaft. In thismanner, the protruding portion creates a volume of revolution as theasymmetrical tip rotates, which facilitates crossing a vascularocclusion.

The asymmetrical rotating tip may includes an ultrasonic transducer oran optical fiber device mounted therein, to thereby obtain guidanceinformation as the guidewire advances through the patient's vasculature.The drive member may be a drive shaft having a lumen therethrough toaccommodate electrical leads connected to the ultrasonic transducer orthe optical fiber, connected to an imaging device near the proximal endof the guidewire shaft. The ultrasonic transducer may be recessed withina well disposed within the asymmetrical rotating tip. The protrudingportion of the asymmetrical rotating tip may project from the outersurface of the guidewire shaft by a distance selected within a range of0.002 inches to 0.010 inches. The actuator may be a motorized actuator,a manual actuator, or a combination of these. The guidewire shaft mayinclude a coiled wire and a polymeric tube in intimate contact with anouter diameter of the coil. In this manner, the tube in intimate contactwith the coil prevents the coiled wire from buckling in or out when theguidewire is pushed through the patient's vasculature, therebyincreasing the pushability and the column strength of the guidewirewithout substantially reducing its flexibility. The tube may be formedof, for example, polyimide or heat shrinkable TEFLON. A coupling membermay be disposed between the distal end of the guidewire shaft and theasymmetrical rotating tip, the coupling member being bonded to thedistal end of the shaft by an adhesive.

According to another exemplary embodiment of the present invention, aguidewire for crossing a vascular occlusion, comprises:

a guidewire shaft having a proximal end and a distal end;

a rotating drive member having a proximal and a distal end;

a coupling member attached to a distal end of the shaft, and having athrough opening aligned with a longitudinal axis of the guidewire shaftto allow the drive member to rotate and slide therein, the couplingmember including a distal angled surface oriented at predetermined acuteangle relative to a plane perpendicular to the longitudinal axis of theguidewire shaft; and

an asymmetrical tip attached to the distal end of the drive member anddriven in rotation about the longitudinal axis of the guidewire shaft bythe drive member, the asymmetrical tip including a proximal angledsurface that, in one orientation, is parallel to and in intimate contactwith the distal angled surface of the coupling member. In this manner,rotation of the asymmetrical tip against the distal angled surface ofthe coupling member causes the asymmetrical tip to reciprocate along theaxis of the guidewire shaft over a distance determined at least by thepredetermined angle, to thereby facilitate a crossing of a vascularocclusion by submitting the occlusion to both rotational andreciprocating movement of the asymmetrical tip.

A spring may be disposed near the proximal end of the drive member tobias the drive member in a proximal direction by a substantiallyconstant force. The predetermined acute angle may be an angle selectedwithin the range of about 2° to about 45°. The distal angled surface maybe non-planar and may include one or more topographical features, andthe proximal angled surface may be a mating non-planar surface includingat least one corresponding topographical feature.

According to another preferred embodiment of the present invention, acatheter for treating vascular occlusions, comprises:

a catheter shaft having a proximal end and a distal end;

a rotating drive shaft member having a proximal and a distal end, thedrive shaft member being disposed within and along a longitudinal axisof the shaft;

a guidewire disposed within the rotating drive shaft member;

a coupling member attached to a distal end of the catheter shaft, andhaving a through opening aligned with a longitudinal axis of the shaftto allow the drive shaft member to rotate and slide therein, thecoupling member including a distal angled surface oriented atpredetermined acute angle relative to a plane perpendicular to thelongitudinal axis of the shaft; and

an asymmetrical tip attached to the distal end of the drive shaft memberand driven in rotation about the longitudinal axis of the shaft by thedrive member, the asymmetrical rotating tip including a proximal angledsurface that, in one orientation, is parallel to and in intimate contactwith the distal angled surface of the coupling member, the asymmetricalrotating tip including an axial through bore for receiving theguidewire. In use, the guidewire is advanced near an occlusion site,whereupon the catheter is tracked over the guidewire to the occlusionsite and the guidewire retracted within the catheter shaft. Rotation ofthe asymmetrical tip against the distal angled surface of the couplingmember causes the asymmetrical tip to reciprocate and to displace andexert pressure on the occlusion, to thereby create a dissection planealong which the catheter may further advance.

The predetermined acute angle may be selected within the range of about2° to about 45°. Alternatively, the predetermined acute angle may besubstantially 0°. The asymmetrical tip may include a transducer or anoptical fiber device mounted therein, to thereby obtain guidanceinformation as the catheter advances through the patient's vasculature.The drive shaft member may be a drive shaft having a lumen therethroughto accommodate electrical leads connected to the transducer or theoptical fiber, connected to an imaging device near the proximal end ofthe catheter shaft. The transducer may be recessed within a welldisposed within the asymmetrical rotating tip. The asymmetrical tip mayinclude a protrusion smoothly projecting in a radial direction relativeto the longitudinal axis of the catheter shaft, the protuberancebreaking a plane defined by an outer diameter of the catheter shaft. Inthis manner, the protruding portion creates a cylindrical volume ofrevolution as the asymmetrical tip rotates and reciprocates.

According to a still further embodiment of the present invention, aninstrument for crossing a vascular occlusion, comprises:

a shaft having a proximal end and a distal end;

a rotating drive member having a proximal and a distal end;

a coupling member attached to a distal end of the shaft, and having athrough opening aligned with a longitudinal axis of the shaft to allowthe drive member to rotate and slide therein, the coupling memberincluding a distal angled surface, the distal angled surface beingoriented at predetermined angle relative to a plane perpendicular to thelongitudinal axis of the shaft, and

a symmetrical tip attached to the distal end of the drive member anddriven in rotation about the longitudinal axis of the shaft by the drivemember, the symmetrical tip including a proximal angled surface that, inone orientation, is parallel to and in intimate contact with the distalangled surface of the coupling member. In this manner, rotation of thesymmetrical tip against the distal angled surface of the coupling membercauses the symmetrical tip to reciprocate along the axis of the shaft,to thereby facilitate a crossing of a vascular occlusion by submittingthe occlusion to both rotational and reciprocating movement of thesymmetrical tip.

The distal angled surface of the coupling member and the proximal angledsurface of the symmetrical tip may be substantially planar.Alternatively, the distal angled surface of the coupling member and theproximal angled surface of the symmetrical tip may be substantiallynon-planar and may include mating topographical features. The distalangled surface of the coupling member and the proximal angled surface ofthe symmetrical tip may also be substantially non-planar and may includemating topographical features, and the predetermined angle may besubstantially 0°. Alternatively still, the distal angled surface of thecoupling member and the proximal angled surface of the symmetrical tipmay be substantially non-planar and may include mating topographicalfeatures, and the predetermined angle may be selected within a range ofabout 2° to about 45°.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the objects and advantages of the presentinvention reference should be made to the following detaileddescription, taken in conjunction with the accompanying figures, inwhich:

FIG. 1A is a cross sectional diagram of a guidewire having a rotatingasymmetrical tip according to one embodiment of the present invention.

FIG. 1B is a cross sectional diagram of a guidewire having a rotatingasymmetrical tip according to another embodiment of the presentinvention.

FIG. 2 is a cross sectional diagram of a detail of the guide wire shaftwall according to an embodiment of the present invention.

FIG. 3A is a cross sectional diagram of a guide wire having a rotatingand reciprocating asymmetrical tip according to another embodiment ofthe present invention, wherein the asymmetrical tip is in a firstorientation.

FIG. 3B is a cross sectional diagram of a guide wire having a rotatingand reciprocating asymmetrical tip according to another embodiment ofthe present invention, wherein the asymmetrical tip is in a secondorientation.

FIG. 4A is a cross sectional detailed view of another embodiment of acoupling member and of a corresponding asymmetrical tip, according tothe present invention.

FIG. 4B is a cross sectional detailed view of another embodiment of acoupling member and of a corresponding asymmetrical tip, according tothe present invention.

FIG. 5 is a cross sectional diagram of a catheter according to anotherembodiment of the present invention.

FIG. 6A is a cross sectional detailed view of another embodiment of thepresent invention, showing a coupling member and a correspondingsymmetrical tip.

FIG. 6B is a cross sectional detailed view of yet another embodiment ofthe present invention, showing a coupling member and a correspondingsymmetrical tip.

FIG. 6C is a cross sectional detailed view of a further embodiment ofthe present invention, showing a coupling member and a correspondingsymmetrical tip.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1A and 1B show cross-sections of guide wires with rotatingasymmetrical tips according to the present invention. Reference numeral105 is a guidewire shaft. To navigate the small diameter and tortuousregions of a patient's vasculature, the guidewire shaft 105 must beflexible. To achieve this goal, the guidewire shaft 105 according to thepresent invention, as shown in FIG. 2, may include a tightly coiled wireor ribbon 150. The coiled wire ribbon 150 may be formed of stainlesssteel or a super-elastic metal such as NITINOL ®. In one embodiment, thecoiled wire or ribbon 150 is 0.002 inches in thickness.

In addition to a high degree of flexibility, the guidewire shaft 105must exhibit good column strength, to enhance its ability to be pushedthrough small diameter lumens. To do this, the wire or ribbon coil 150is surrounded by a thin walled polymeric tube 140 in intimate contacttherewith. The thin walled tube 140 prevents the wire or ribbon coil 150from buckling inward or outward when the guidewire shaft 105 is pushedthrough the patient's vasculature. Moreover, while the thin walled tube140 increases the column strength of the guidewire shaft 105, it doesnot substantially decrease its flexibility. Therefore, the guidewireshaft 105 according to the present invention exhibits a high degree offlexibility as well as a good column strength, which increases itspushability and therefore improves the overall functionality of thedevice.

The thin walled tube 140 may be formed of polyimide having a thicknessof approximately 0.0005 inches or greater. Alternatively, a heatshrinkable TEFLON® or PTFE tubing may be utilized, having a wallthickness of about 0.002. TEFLON® has the advantage that it isinherently slippery, which facilitates the guide wire's travels throughtight and tortuous regions of the patient's vasculature. According toone embodiment of the present invention, the thin walled tube 140 isabout 0.002 inches thick and the coiled wire or ribbon 150 is also 0.002inches in thickness, for a total wall thickness of about 0.004 inches inthickness.

As shown in FIGS. 1A and 1B, disposed within and along the longitudinalaxis of the guidewire shaft 105 is a rotating drive wire 120. In oneembodiment, the rotating drive wire 120 is about 0.005 inches and madeof stainless steel. The proximal end of the drive wire 120 is attachedto an actuator 180. The actuator 180 may either be a manual or motorizedactuator, or a combination of the two. The actuator 180 rotates thedrive wire 120 at a slow angular speed, within a range of about 2 toabout 500 revolutions per minute. A manual actuator may be preferred forthose interventions requiring precise manual control. In such a case,the actuator 180 may include a knob for manually rotating the drive wire120, or for causing it to alternate between a forward and reversedirection, depending upon the desired therapeutic effect.

Near its distal end, the drive wire 120 runs through a coupling member110. The coupling member 110 includes an opening aligned with thelongitudinal axis of the guidewire shaft 105, allowing the drive wire120 to rotate and to slide therethrough. The coupling member 110 ispreferably made of a hard material. In one embodiment, this hardmaterial is selected from a group consisting of 440, 304 or 316stainless steel, titanium, titanium alloy or any hard material thatprovides a good hard bearing surface. The coupling member 110 is securedto the guidewire shaft 105 by means of an adhesive.

The distal surface 155 of the coupling member 110, in the embodimentsillustrated in FIGS. 1A and 1B, is smooth and perpendicular to thelongitudinal axis of the guidewire shaft 105, giving the coupling member110—guidewire shaft 105 assembly a right cylindrical shape.

The distal end of the drive wire 120 is attached to an asymmetricalrotating tip 115. The asymmetrical rotating tip 115, according to thepresent invention, has an atraumatic distal end, which is relativelyrounded and smooth. The asymmetrical tip 115 includes a protuberance117, which projects smoothly therefrom, breaking a plane 118 defined bythe outer diameter 119 of the guidewire shaft 105. This protuberance 117may also simply be a convex portion of the tip 115 that locally projectsfurther in the radial direction than the remainder of the tip 115. Theasymmetrical tip 115 may also include a non-projecting portion 116,which is substantially co-planar with the plane 118 of the guidewireshaft 105. This co-planar non-projecting portion 116 of the asymmetricaltip 115 may be disposed generally radially opposite the protuberance117. The asymmetrical tip 115 may also made of a hard material, and maybe formed of the same material, as is the coupling member 110. In oneembodiment of the present invention, the protuberance 117 projects fromthe plane 118 of the guidewire shaft a distance of about 0.002 to 0.010inches.

In use, the guidewire 100 according to the present invention isintroduced into the patient's vasculature, and advanced near the lesionor occlusion site. The drive shaft 120 rotates, under the action ofeither a manual or motorized actuator 180. As the drive shaft 120 isattached to the asymmetrical tip 115, the asymmetrical tip 115 rotatestherewith. As the guide wire according to the present invention is smallin size and very flexible, it is able to access a very small andtortuous lumen to reach the site of interest, where other, largerdevices could not. One of the primary reasons for failure of commoninterventional procedures is the inability to cross a heavily stenosedregion, where there is little or no channel left through and across theocclusion. By virtue of its flexibility and small size, the guidewireaccording to the present invention can be manipulated extremely close tosuch potentially life threatening occlusions. Once properly positionedat the site of interest, the asymmetrical tip 115 is rotated. As theprotuberance 117 rotates, it sweeps a volume of revolution and displacesany mass it encounters in its path. As the lumen is quite narrow, theocclusive tissue is forced against the protuberance 117. In so doing, itmay be flattened and/or compressed, in the case of soft or fattydeposits, under the combined pressure exerted by the protuberance 117and the vessel walls. Alternatively, in the case of hard and calcifieddeposits such as plaque, the force exerted by the protuberance 117 ofthe asymmetrical tip 115 can break, displace and/or exert pressure onsuch deposits and create a dissection plane along which the guidewire100 may further advance. In this manner, a channel through which bodyfluids such as blood may more freely pass may be created or widened.Alternatively still, the soft fatty deposits or the hard calcifieddeposits may be compressed and/or broken up to allow the guide wireaccording to the present invention to cross the occlusion site. Onceacross, a sheath may be slipped over the guidewire shaft and across theocclusion. Thereafter, the guide wire 100 may be retracted, removed fromthe patient's body, and exchanged for a standard guidewire over whichanother interventional tool may be tracked. Such interventional tool maybe an atherectomy device, a balloon angioplasty device, a stentplacement tool or the like. These devices may now be successfully beemployed where they otherwise might not have been, as the occlusion hasbeen crossed, and a channel therethrough created or sufficientlyenlarged to allow their effective use.

According to another embodiment of the present invention, theasymmetrical and atraumatic tip 115 includes an imaging transducer 130,such as an ultrasonic transducer as shown in FIG. 1A or an optical fiber126 as shown in FIG. 1B. As shown in FIG. 1A, an ultrasonic transducer130 is disposed within the asymmetrical tip 115. This ultrasonictransducer 130 will create an image of the vessel walls and anyocclusions thereof, to allow the guide wire 100 according to the presentinvention to stay within the desired boundaries and successfullynegotiate the tortuous vessels in which the occlusion may be located.When an imaging transducer, whether ultrasonic or optical is presentwithin the asymmetrical tip 115, reference numeral 120 designates ahollow drive shaft, as opposed to a solid drive wire. This allowselectrical leads 125, in the case of the ultrasonic transducer 130 shownin FIG. 1A, or an optical fiber 126, as shown in FIG. 1B, to be disposedwithin the lumen of the drive shaft 120. When an ultrasonic transducer130 is utilized, the transducer should be recessed from the surface ofthe asymmetrical tip 115. For this purpose, a well 135 is formed withinthe asymmetrical tip 115. This prevents the ultrasonic transducer 130from generating too much energy too close to the target tissue, toprevent the phenomenon known as “ring down”. The electrical leads 125are then connected to an imaging device 170, to display an image of thetissue toward which the energy is directed. Alternatively, an opticaltransducer may be used, and embedded within the asymmetrical tip 115. Anoptical fiber 126 would then be disposed within the drive shaft 120 andconnected, at its proximal end, to an optical imaging device 170. Theresultant image may then be processed, using a variety of knowntechniques, such as OCT, or Optical Coherence Tomography. Examples ofsuch processing are given in U.S. Pat. No. 5,321,501 issued on Jun. 14,1994 to Swanson et al. and U.S. Pat. No. 5,459,570 issued Oct. 17, 1995to Swanson et al., the disclosures of which are incorporated herewith intheir entirety.

Of course, the guidewire 100 according to the present invention need notincorporate a transducer within the asymmetrical tip 115, to betherapeutically effective. Thus, the present invention is not to belimited to those embodiments wherein an imaging device is present withinthe asymmetrical tip 115.

FIG. 3A and FIG. 3B show another embodiment of the present invention.FIGS. 3A and 3B show a guide wire 300 that is similar to the guidewire100 of FIG. 1, but for the coupling member and the asymmetrical tip. Thedescription of the guidewire 100 of FIGS. 1 and 2, with the exception ofthe description of the coupling member 110 and the asymmetrical tip 115,therefore, is incorporated herewith by reference.

The embodiment of the guidewire 300 of FIGS. 3A and 3B includes acoupling member 310, as well as a correspondingly shaped asymmetricaltip 315. The coupling member 310 includes a distal angled surface 355oriented at a predetermined acute angle theta relative to a plane 312that is perpendicular to the longitudinal axis 390 of the catheter shaft305. This angle theta may be selected within the range of 2° to 45°.Therefore, unlike the embodiment of the guidewire 100 shown in FIG. 1,the guidewire 300 according to the present invention shown in FIGS. 3Aand 3B includes a coupling member 310 having an angled distal surface355. The asymmetrical tip 315 includes a correspondingly angled proximalsurface 360. The proximal angled surface 360 of the asymmetrical tip 315is angled at the same predetermined angled theta, as measured relativeto a plane 313 that is perpendicular to the longitudinal axis 390 of thecatheter shaft, as is the distal angled surface 355 of the couplingmember 310. The tip 315 may be symmetrical. Alternatively, the tip 315may be asymmetrical and may include a protuberance 317 or convex portionthat is similar to the protuberance 117 illustrated in FIG. 1 anddescribed in detail above. This detailed description, therefore, isincorporated herewith in its entirety. In the orientation of theasymmetrical tip 315 relative to the coupling member 310 shown in FIG.3A, the angled proximal surface 360 is parallel to and in intimatecontact with the distal angled surface 355 of the coupling member 310.In the orientation of the asymmetrical tip 315 shown in FIG. 3A, theangled proximal surface 360 is in full bearing contact with the angleddistal surface 355 of the coupling member 310.

As the shaft rotates under the action of the actuator 180 (shown inFIGS. 1A and 1B), the asymmetrical tip 315 of the guide wire 300 of FIG.3A rotates also. As the asymmetrical tip 315 rotates, the two angledsurfaces 355, 360 bear against one another. As the drive wire or driveshaft 320 is mounted within the catheter shaft 305 so as to allow bothrotation about and translation along the longitudinal axis 390 of thecatheter shaft, the asymmetrical tip 315 attached thereto follows areciprocating motion as it bears against the angled distal surface 355of the coupling member 310.

FIG. 3B also shows the guidewire 300, the asymmetrical tip 315 havingrotated approximately 180° away from the position shown in FIG. 3A. Dueto the co-action of the two angled surfaces 360 and 355 bearing againstone another, the asymmetrical tip 315 shown in FIG. 3B is located at itsmaximum longitudinal displacement relative to the coupling member 310.This longitudinal displacement of the asymmetrical tip 315 is madepossible by the angled surfaces 355, 360 as well as by the ability ofthe drive shaft or drive wire 305 to slide along the longitudinal axis390 of the guidewire shaft 305. The longitudinal displacement of theasymmetrical tip 315 relative to the distal most portion of the couplingmember 310 is determined by the angle theta of both the asymmetrical tip315 and the coupling member 310. For example, if the outside diameter ofa guidewire shaft is 0.0225 inches and a longitudinal displacement of0.010 inches is desired, the tangent of the angle theta must be0.010/0.0225 or 0.4444, making the angle theta equal to approximately24°. Other displacements may be chosen, by appropriately matching theangle theta to the outside diameter of the guidewire shaft 305 or thecoupling member 310.

As the asymmetrical tip 315 shown in FIG. 3B is further driven inrotation about the longitudinal axis of the guidewire shaft, i.e.,completing its revolution from the 180° position to the 360° position,it will return to the orientation shown in FIG. 3A. Therefore, as theasymmetrical tip 315 rotates, it will describe a reciprocating motionfrom the position shown in FIG. 3A to the position shown in FIG. 3B, andback.

To insure the return of the asymmetrical tip 315 from the position shownin FIG. 3B to the position shown in FIG. 3A, the rotating drive shaft ordrive wire 305 may be biased by a substantially constant force directedin the proximal direction. This substantially constant force may besupplied by a spring 395 attached at or near the proximal end of thedrive wire or shaft 320.

In use, the guidewire 300 is advanced near an occlusion site within thepatient's vasculature. The rotation of the asymmetrical tip 315 againstthe distal angled surface 355 of the coupling member 310 then causes theasymmetrical tip 315 to reciprocate along the axis of the shaft 305 overa distance determined by the angle theta, as described above. Thecrossing of the vascular occlusion is thereby facilitated, as theocclusion is submitted to both rotational and reciprocating movement ofthe asymmetrical tip 315. Within the tight confines of the vessel wallsand the constriction caused by the stenotic material at the occlusionsite, this rotational and reciprocating motion exerts pressure on theocclusion over a cylindrical volume of space. Specifically, theprotuberance 317 projecting from the plane defined by the outsidediameter of the guidewire shaft 305 exerts radially directed pressureand displaces and/or breaks up a volume of stenotic material equal toits own volume. In this manner, a channel may be formed through theocclusion, or an existing channel widened. Thereafter, as with the firstembodiment of the present invention, a sheath (not shown) may be slidover the guide wire 300, the guide wire 300 retracted and exchanged fora standard guidewire. A new interventional tool may then be tracked overthis standard guidewire and placed into position across the occlusionto, for example, place a stent, perform an angioplasty or atherectomyprocedure, or the like. The present invention, therefore, is especiallyuseful where there is a total or near total chronic blockage of a bloodvessel or any biological vessel, where this blockage or occlusion doesnot allow conventional instruments to cross or to reach the site ofinterest. After the guidewire 300 according to the present invention isemployed, the stenotic material may be sufficiently compressed,displaced and/or broken up to allow the use of the aforementionedinterventional tools to be utilized with a high degree of success.

It is to be noted that the guidewire of FIGS. 3A and 3B may be providedwith either an ultrasonic transducer 130 or an optical transducer 126,in the same manner as described relative to FIGS. 1A and 1B. Thedescription of such transducers and the means of connecting them to theproximal imaging device 170, therefore, is incorporated herewith in itsentirety, as if repeated here in full.

Other configurations of the coupling member and tip may be employed. Forexample, as shown in FIG. 4A, the angled distal surface 455A of thecoupling member 410 or, as shown in FIG. 4B, the distal surface 455B ofthe coupling member 410 may be non-planar and include a number oftopographical features such as ridges, peaks and valleys, bumps,depressions or other similar features, which alter the motion of theasymmetrical tip 415 as the asymmetrical tip 415 is driven by the drivewire or shaft 420. In FIG. 4A, the angle theta has a non-zero value,while it is zero in FIG. 4B. The proximal surface 460A, 460B of theasymmetrical tip 415, in FIGS. 4A and 4B, respectively, would then alsobe non-planar and be provided with corresponding topographical featuresto insure a mating relationship with distal surfaces 455A, 455B,respectively.

Alternatively, as shown in FIGS. 6A through 6C, the tip of theguidewires or the catheters according to the present invention may besymmetrical about the longitudinal axis of the guidewire or cathetershaft. For example, as shown in FIGS. 6A and 6C, the angled distalsurfaces 655A, 655C of the coupling member 610A, 610C may be planar(FIG. 6A) or non-planar (FIG. 6C) and include a number of topographicalfeatures such as ridges, peaks and valleys, bumps, depressions or othersimilar features, which alter the motion of the symmetrical tip 615A,615C as the symmetrical and atraumatic tip 615A, 615C is driven by thedrive wire or drive shaft 620. The proximal surface 660A, 660C of thesymmetrical tip 615A, 615C in FIGS. 6A and 6C, respectively, would thenalso be non-planar and be provided with corresponding topographicalfeatures to insure a mating relationship with distal surfaces 655A,655C, respectively. In FIGS. 6A and 6C, the angle theta has a non-zerovalue.

Alternatively still, as shown in FIG. 6B, the coupling member 610B couldbe provided with a distal surface 655B that is non-planar and thatincludes a number of topographical features such as ridges, peaks andvalleys, bumps, depressions or other similar features, which alter themotion of the symmetrical and atraumatic tip 615B as the symmetrical tip615B is driven by the drive wire or drive shaft 620. The proximalsurface 660B of the symmetrical tip 615B in FIG. 6B would then also benon-planar and be provided with corresponding topographical features toinsure a mating relationship with distal surfaces 655B. In contrast toFIGS. 6A and 6C, the angle theta in FIG. 6B has a substantially zerovalue.

The coupling member-tip configurations shown in FIGS. 4a, 4B, 6A, 6B and6C are readily applicable to both the guide wire and catheterconfigurations shown in FIGS. 1A, 1B, 3A and 3B and FIG. 5.

For example, the asymmetrical tip 115 of FIG. 1 could be caused toundergo a certain measure of reciprocal motion by providing the distalsurface 155 of the coupling member 115 with a number of smooth peaks andvalleys or bumps and depressions, and by providing the proximal surface160 of the asymmetrical tip 115 with corresponding and mating features.Such features may also be employed in the embodiment of the guidewireaccording to the present invention shown in FIGS. 3A and 3B.

In this manner, for example, another motion of different amplitude maybe superimposed upon the reciprocating motion of the asymmetrical tip415 caused by the angled surfaces 455A, 460B, by providing therespective surfaces with topographical features, such as bumps anddepressions or a series of ridges.

FIG. 5 shows another embodiment of the present invention. FIG. 5illustrates a catheter 500 with a rotating and reciprocatingasymmetrical tip 515. The catheter 500 includes a catheter shaft 505.The catheter shaft 505, in one embodiment, has an outer diameter of0.050 inches. Disposed along the longitudinal axis of and within thecatheter shaft 505, is a rotating drive shaft 520 formed of, forexample, stainless steel, a titanium alloy, or the like. In oneembodiment, the rotating drive shaft 520 has an outer diameter of 0.040inches. The proximal end of the drive shaft 520, as shown in FIG. 1, isconnected to an actuator 180, which may be manual, motorized or acombination thereof. The distal end of the rotating drive shaft 520 isembedded within the asymmetrical tip 515, to cause the tip 515 to rotatealong with the drive shaft 520. Disposed within the lumen of the driveshaft 520 is a guidewire 570 made of, for example, a super elastic metalsuch as NITINOL®, stainless steel or some other suitable material. Inone embodiment of the catheter 500 according to the present invention,the guidewire 570 has an outer diameter of 0.014 inches.

A coupling member 510 is attached to the distal end of the cathetershaft 505. The coupling member 510 includes a through opening alignedwith the longitudinal axis of the catheter shaft 505 to allow the driveshaft 520 to rotate and to slide therethrough. The coupling member 510further includes a distal angled surface 555 oriented at predeterminedacute angle theta relative to a plane 512 that is perpendicular to thelongitudinal axis of the catheter shaft 505.

An asymmetrical and atraumatic rounded tip 515 is attached to the distalend of the rotating drive shaft 520, and is driven in rotation about thelongitudinal axis of the catheter shaft 505. The asymmetrical rotatingtip 515 includes a proximal angled surface 560 that, in one orientation,is parallel to and in intimate contact with the distal angled surface555 of the coupling member 510. The proximal surface 560 is alsoinclined relative to a plane 513 that is perpendicular to thelongitudinal axis of the catheter shaft, at the same angle theta as thedistal angled surface 555 of the coupling member 510. The asymmetricalrotating tip 515 also includes an axial through bore 571 for receivingthe guidewire 570, the guidewire 570 emerging from the asymmetrical tip515 at the distal most portion 572 thereof.

The angle theta may be selected within a range of about 2° to about 45°.In one embodiment, the distance over which the asymmetrical tip travelsis on the order of 0.015 inches. As the outer diameter of the cathetershaft 505, in one embodiment is 0.050 inches, it follows that the angletheta, which will achieve this reciprocating travel distance, is about17°.

The asymmetrical tip 515 of the catheter 500 may also include ultrasonicor optical transducers embedded therein, in the same manner as wasdescribed relative to the inventions shown in FIGS. 1A through 3B. Thedescriptions thereof are, therefore, incorporated herewith.

To insure that the asymmetrical tip 515 returns to its proximal mostposition illustrated in FIG. 5 after having rotated 180°, the rotatingdrive shaft 520 may biased by a substantially constant force directed inthe proximal direction. A spring 395, as shown in FIG. 3A and 3B may,therefore, be attached to the drive shaft 520 near its proximal end,which spring 395 will bias the asymmetrical tip 515 in the proximaldirection and insure that the reciprocating movement of the tip 515 issustained.

In use, the guidewire 570 is advanced near an occlusion site, whereuponthe catheter 500 is tracked over the guidewire 570 to the occlusionsite. The distal end of the guidewire 570 is then retracted within thecatheter shaft 505. The rotation of the proximal surface 560 of theasymmetrical tip 515 against the distal angled surface 555 of thecoupling member 510 then causes the asymmetrical tip 515 to reciprocate,thus displacing and exerting pressure on the occlusion. This creates adissection plane along which the catheter may further advance. The forceexerted by the rotation and reciprocal motion of the asymmetrical tip515 upon the stenotic tissue may compress or break up the occlusion. Anexisting channel through the occlusion may be enlarged or a totallyoccluded vessel may be provided with a new channel through which theguidewire 570 may be further advanced. This guidewire 570, thereafter,may be left in place within the patient's vasculature, and the catheter500 removed and exchanged for another interventional tool, which may betracked over the guidewire 570 to the lesioned or occluded site forfurther procedures.

The non-planar surfaces 455A, 460A described relative to FIG. 4A may besubstituted for the distal angled surface 555 of the coupling member 510and the proximal angled surface 560 of the asymmetrical and atraumatictip 515 of the catheter 500, respectively. These descriptions,therefore, are omitted to avoid unnecessary repetition and areincorporated herewith in their entirety.

While the foregoing detailed description has described preferredembodiments of the present invention, it is to be understood that theabove description is illustrative only and not limiting of the disclosedinvention. For example, the various elements of the guide wires and thecatheter may be formed of materials other than those specificallyenumerated without, however, departing from the scope and spirit of thepresent invention. Moreover, the angle theta for both the distal surfaceof the coupling member and the proximal surface of the asymmetrical tipmay be zero. In such a case, to achieve the reciprocal motion describedabove, the above-cited surfaces may include a number of topographicalfeatures. Further modifications will occur to those of skill in thisart, and all such modifications are deemed to fall within the scope ofthe present invention. Thus, the invention is to be limited only by theclaims as set forth below.

What is claimed is:
 1. An instrument for crossing a vascular occlusion,comprising: a non-rotating shaft; a drive member within the shaft thatrotates about a longitudinal axis of the shaft; a non-rotating couplingmember attached to a distal end of the shaft, wherein the drive memberrotates within the coupling member, the coupling member including adistal angled surface oriented at an angle relative to a planeperpendicular to the longitudinal axis of the shaft; and an atraumatictip attached to a distal end of the drive member and driven in rotationabout the longitudinal axis of the shaft by the drive member, whereinthe tip is for contacting the vascular occlusion and displacing materialcausing the vascular occlusion, the tip including a proximal angledsurface in contact with the distal angled surface such that in a firstradial position the distal angled surface and the proximal angledsurface are substantially in contact over both of the respectivesurfaces, wherein rotation of the tip out of the first radial positioncauses the tip to reciprocate along the longitudinal axis of the shaftwith respect to the coupling member as a result of a force exerted onthe proximal angled surface by the distal angled surface.
 2. Theinstrument of claim 1, wherein the distal angled surface of the couplingmember and the proximal angled surface of the tip are substantiallyplanar.
 3. The instrument of claim 1, wherein the distal angled surfaceof the coupling member and the proximal angled surface of the tip aresubstantially non-planar and include mating topographical features. 4.The instrument of claim 1, wherein the distal angled surface of thecoupling member and the proximal angled surface of the tip aresubstantially non-planar and include mating topographical features, andwherein the angle comprises an angle selected from a group comprisingthe range of 2 degrees to 45 degrees.
 5. The instrument of claim 1,wherein the tip is rounded and substantially symmetrical with respect tothe longitudinal axis of the shaft.
 6. The instrument of claim 1,wherein the tip is rounded and is asymmetrical with respect to thelongitudinal axis of the shaft.
 7. An instrument for crossing a vascularocclusion, comprising: a shaft; a drive member within the shaft thatrotates about a longitudinal axis of the shaft; a coupling memberattached to a distal end of the shaft, the coupling member including asubstantially planar distal angled surface oriented at an angle relativeto a plane perpendicular to the longitudinal axis of the shaft; and asymmetrical tip attached to a distal end of the drive member and drivenin rotation about the longitudinal axis of the shaft by the drivemember, the symmetrical tip including a substantially planar proximalangled surface in contact with the substantially planar distal angledsurface such that the symmetrical tip reciprocates along thelongitudinal axis of the shaft with respect to the coupling memberduring rotation.
 8. An instrument for crossing a vascular occlusion,comprising: a shaft; a drive member within the shaft that rotates abouta longitudinal axis of the shaft; a coupling member attached to a distalend of the shaft, the coupling member including a substantially planardistal angled surface oriented at an angle relative to a planeperpendicular to the longitudinal axis of the shaft; and an asymmetricaltip attached to a distal end of the drive member and driven in rotationabout the longitudinal axis of the shaft by the drive member, whereinthe asymmetrical tip is asymmetrical with respect to a radius measuredfrom the longitudinal axis of the shaft, the asymmetrical tip includinga substantially planar proximal angled surface in contact with thesubstantially planar distal angled surface such that the asymmetricaltip reciprocates along the longitudinal axis of the shaft with respectto the coupling member during rotation.